This invention relates to a device for sewing on buttons, incorporating in particular a button-sewing foot which features retaining elements that serve to hold the button against the button-sewing foot in such fashion that, independent of the position of the latter, the needle of the sewing machine can be aligned with a specific button perforation.
Various devices designed for automatic button sewing have already been introduced in the industrial sector. For example, DE 1 037 824 B describes a sewing machine equipped with a special, fixed button-sewing foot. For general-purpose household sewing machines, however, makeshift solutions have had to be employed for attaching buttons to the fabric. In one such known approach the button is placed under a suitable pressure foot and sewed on in zigzag fashion; the drawback here is the partial concealment of the button during the sewing process which can easily lead to a damaged button or needle or a shifting of the button as it is sewed on. Another known practice when sewing on buttons with a stem has been to place a match stick between the pressure foot and the button and to withdraw the match stick after the button is on. The drawback is again the partial concealment of the button and the need to improvise by using a makeshift device such as a match stick.
As a matter of expediency, a button to be attached can be clamped down by lowering the pressure foot. However, while this permits a clear view of the button, the latter is clamped down off center which becomes a problem especially in the case of thick fabrics. Besides, this does not allow for buttons to be sewed on with a stem.
It is the objective of this invention to introduce a device which, by simple manipulation, facilitates the sewing of buttons even on common household sewing machines.
According to the invention, this objective is achieved by means of a button-sewing foot which can be snapped into the pressure-foot holder of the sewing machine and whose retaining elements are essentially in the form of spring clips the two legs of which push from underneath against the perimeter of the button outside the button perforations, clamping the button against the bottom of the button-sewing foot.
The advantage of the button-sewing foot according to this invention which, replacing the regular pressure foot, is snapped into the pressure-foot holder of the sewing machine, is that with the aid of the retaining elements it locks the button immovably in the desired position, thus permitting particularly simple and well-controlled manipulation as the button is sewed on. The retaining elements themselves can help to properly align the button perforations in that, preferably, the operator can see these perforations of the clamped button from the top so as to better control the sewing process and to be able to stop it once enough needle loops have been made. Lifting or lowering the button-sewing foot does not affect proper alignment.
Since the retaining elements clamp the button against the bottom of the button-sewing foot, it is possible by lowering the button-sewing foot to firmly press the button against the fabric without requiring any particularly rigid or sturdy retaining elements.
Using retaining elements in the form of spring clips, whose two legs push from underneath against the perimeter of the button away from the button perforations, allows for particularly simple and cost-effective fabrication, while suitably angled spring-clip legs permit easy insertion of the button between a given surface of the button-sewing foot and said legs. Appropriate stops on the button-sewing foot or a special profile of the spring-clip legs may serve to properly align the button in the desired stitching position. Normally, however, the button is simply slipped in and aligned as required based on the position of the button perforations.
To permit buttons to be attached to the fabric with either a stem or flush without a stem, a particularly preferred embodiment of this invention provides for the device to incorporate a two-position selector slide by means of which it is possible to switch from a first setting for sewing on buttons flush to a second setting which increases the length of the thread as it is looped through the button perforations.
The advantage of this concept of selectable settings lies in the universal suitability of the button-sewing foot, requiring no additional auxiliary elements.
In a first design version the selector slide may be tongue-shaped, permitting its repositioning in a second location above or below the button between the button perforations. When employing this design variation, the added length of the needle loop needed to form the stem is obtained by first sewing over the tongue-shaped selector slide. On completion of the sewing process the selector slide is pushed back into its home position, the fabric and the button are spread apart and the resulting stem is wrapped and tied with thread.
In preferred design enhancements of the adjustable selector slide, the slide is held in place in a guide on the button-sewing foot and can be click-stopped in either position for instance in that the bottom end of a sewing-foot pin is snapped into the pressure-foot holder of the sewing machine while said pin can engage in either one of two mutually distant detents on the upper surface of the tongue-shaped selector slide.
As an alternative to the tongue-shaped selector slide that is adjustable relative to the button perforations, a selector slide may be provided which in its second position constitutes a spacer between the button and the fabric to which the button is to be fastened.
Another possibility is a button-sewing foot which allows for the fastening of a button with a stem not by means of a movable adjustment but instead with the aid of detachable retaining elements, in which case a first set of retaining elements for the flush fastening of a button is interchangeable with a second set of retaining elements for sewing on a button with a stem.
In this design version of the button-sewing foot, the insertion of the second set of retaining elements that serves for sewing on a button with a stem, forces a certain distance from the fabric even with the sewing foot lowered, thus providing that extra length of the needle loop required for forming the stem in the sewing process. The retaining elements may again be in the form of spring clips, in which case the legs of the second set of retaining elements define a specific spacing between the fabric and the button.